Tempered Glass HD Clear
Another route is a tempered and strengthened glass from YIHAILU. While the image is of a different Moto device, they confirmed this is specifically for the Moto X4. Each piece of glass they use is chemically strengthened for ultimate durability. Additionally, it's only 0.28mm thin, so you'll barely notice there is any glass on your phone at all.
Most screen protectors are around 0.33mm thick, and more noticeable than you'd expect. That isn't the case with this protector. The thin design allows it to have a natural feeling on your fingers, instead of feeling like a screen protector. It might not be as durable as other glass, but it's a good middle ground for those in need.